Temperature control device for oil burners



Patented Oct. 24, 1933 TEMPERATURE CONTROL DEVICE FOR OIL BUR Elliott D. Harrington,

NERS

Schenectady, N. Y., as-

signor to General Electric Company, a. corporation of New York Application August 25,

1% Claims.

My invention relates to control devices, more particularly temperature control devices for liquid fuel burning apparatus.

Most oil burners operate on the on and off principle or on the high-low principle. That is, the burner in the first case is either operating at its maximum capacity or it is entirely shut off. In the second case, the burner is operated either with a very high flame or a low flame. The first method is not emcient since it forces the boiler at maximum load whenever the burner is in operation and the second method fails to provide a low enough reliable flame in moderate weather.

It has been found that the average domestic boiler operates at highest emciency between 25% and 50% load. At 100% the efiiciency is relatively lower and. when the burner is shut down as in the on-oif method of burning oil, the boiler becomes a radiator and the air drawn through the heating passages by natural draft cools the boiler and wastes heat up the chimney, Therefore, the ideal control system should only generate heat at the rate at which it is being radiated from the home, thereby operating for a great portion of the total heating season at the peak on the eiiiciency curve of 25% to 50% load. The commonly accepted system of control operates the boiler at 100% load whenever heat is required'and shuts down entirely whenever there is no demand for the heat, thus operating at the two most disadvantageous points on the efilciency curve.

It is the object of my invention to provide a temperature control system which will operate an oil burner heating apparatus at its best ciliciency.

More specifically, the object of my invention is to provide an oil burner control responsive to both the inside and outside temperature condi tions for operating an oil burner at its best em= ciency.

Briefly, in the preferred embodiment of my invention I provide a device for regulating the oil and air supplied to the oil burner furnace which device is under the joint control of an outside temperature responsive device and an inside temperature responsive device. The control is so constructed that the flame may be made high or low for approximately satisfying the heat requirements by means of the outside temperature responsive device which responds to temperatures below a predetermined value and to temperatures above another predetermined value. Intermediate these temperatures only the inside temperature responsive device controls 1931. Serial No. 559,232

the burner. In addition the inside temperature responsive device whichbrings about finer adjustment of the flame independently controls the regulating device for the oil and air in any position in which it might have been moved in response to the demands of the outside temperature responsive device. The inside temperature responsive device also controls the oil burner motor to deenergize the same if inside temperatures exceed a predetermined value. In this way the flame can be regulated in response to the heat requirements of the building to be heated. By this method the advantages of a high-low flame and an on-off system are combined and the disadvantages resulting in inefficient operation of the burner apparatus by using each method alone is eliminated.

The single figure in the drawing represents a schematic diagram of my control system for a liquid fuel burning apparatus.

iii Referring to the drawing, the-air duct 11 and oil spraying nozzle 12 are placed within the combustion chamber of an oil burner furnace 10. Ignition electrodes 13 are placed adjacent there" to for igniting the oil spray. Flame thermostat 14 controls the circuit through the ignition transformer 33 to deenergize the same after flame is established.

An oil burner blower pump unit is mounted on a pedestal beside the furnace and comprises the motor 15, blower 16, and oil pump 17. The oil pump is connected by means of a conduit 18 to the nozzle 12. A valve 18 is mounted in this conduit, and in the position shown which is normal operating position permits a normal flow of oil to the nozzle to provide a normal flame during operation. The air duct ll which is connected to blower 15, has mounted therein a butterfly valve 19 which is normally in the position shown to regulate the fiow of air necessary for providing combustion with the combustion chamber of the furnace 10.

A lever 21 is connected to rotate the butterfly valve 19, under certain conditions to be described below, and the valve 18' has connected thereto the lever 20. The lever 21 and 20 are connected by means of a link 22 so that both the butterfly valve and the oil valve will move in unison.

Pivotally mounted at 25 on the air duct 11 is the control mechanism which comprises the member 24, having mounted thereon the pivoted lever 27 biased against the pin 28 by means of the biasing spring 29 which normally holds the lever 27 against the pin 28. This member 24 also carries an electromagnet 32 for rotating the lever 2'? observed that if the lever 27 is rotated it will in turn rotate the gear section 23 and thus actuate the valves 19 and 18' by means of the lever and link connections to vary the rate of-oil and air supplied to the combustion chamberlo.

A pair of electromagnets 30 and 31 are placed on either side of the member '24 which is normally biased to the position shown in the drawing by means of the biasing spring 26. It will be apparent that if either the electromagnet 30 or electromagnet 31 is energized, that the member 2a carrying the lever 27, spring 29 ,and electromagnet 32 will be rotated about the pivot to operate the two valves described above.

A rotation of member 2a in a counter-clockwise direction produced by electromagnet will partially close the valves from their normal position.

. A rotation of the member 2a in a clockwise direction will open the valves from the normal position to increase the flow of air and oil to the combustion chamber. Thus, the flame may be either decreased or increased from its normal size by rotating the member 24 in the proper direction.

It will also be observed that with the member 24. in either its biased position which is the normal position, or in either its left hand or right hand positions, that the valves may be moved from this setting by movement of the lever 27 when the electromagnet 32 is energized. More specifically, if member 24 is moved in a clockwise di rection to open the valves and thus increase the size of the flame and if the thermostat 35 indicates that more heat must be furnished to bring about the proper room temperature, the lever 27 will be rotated in a clockwise direction to move the valves toward a further open position, thus increasing the size of the flame. It will be observed that this action oan also take place in either the biased position of the member 2a or in the left hand position of the member 24.

The thermostat 3 is responsive to outside temperatures and can be setso that it will move to the right hand contact if the temperature is, for example, below 20 degrees Fahrenheit, or will move to the left hand if the temperature is, for example, 50 degrees Fahrenheit. That is, when the outside temperature is very low the righthand contact will be closed to energize the electromagnet 31 to increase the size of the normal flame. 1f the outside temperature is above 50 degrees Fahrenheit the thermostat 34 will move to the left hand contact to energize the electromagnet 30 to decrease the size of the normal flame.

The thermostat 35 is responsive to room temperatures and when closed upon both contacts will move the member 27 in a clockwise direction to increase the size of the flame being called for by the outside thermostat. When the room temperature reaches that for which the thermostat is set, the lower contact is opened permitting the spring as to rotate member 27 back to its biased position, thus decreasing the sizeof the flame. If the room temperature continues to increase, the upper contact is opened to deenergize the control relay 40 to open the circuit through the oil burner motor 15, thus shutting down the burner. v

The circuits for the various parts of my appa ratus are described below in conne tl ll with the operation of my apparatus. Assuming t the upper contact'ol the thermostat 35 is closed in response to inside temperatures to call for heat, a circuit is completed from the line L1, conductor 41, thermostat 35, relay to, conductor 39 to the other side or the lineLz to energize the relay and move it to the closed position. This completes a circuit through the oil burner motor 15 from-the line La, conductor 33, closed contacts of relay 40, conductor 42, to one side of the fuel supply motor 15 and from the other sideoi the fuel supply motor 15, conductor 44 to the line L1. The fuel supply motor will then operate to rotate the blower 16 and the oil pump 17 to furnish air and oil to the combustion chamber 10, the valves 19 and 18' being positioned as indi cated to supply a normal rate of oil and air for a normal size flame.

The flame detector or flame thermostat 14 is in closed position and a circuit can be traced through the ignition transformer from the line Li, conductor 44., to one side of the primary of the ignition transformer 33, from the other side of the primary of the ignition transformer through conductor 45, flame detector 14, the closed contacts of relay 40, conductor 39, to the other side of the line L2. This energizes the secondary or the transformer and provides a spark between the electrodes 13 to ignite theoil spray. When a flame is established, the flame detector opens the circuit through the ignition transformer and thus deenergizes the ignition system. If the outside thermostat 34 closes its right hand contact in response to low outside temperatures the electromagnet 30 is energized by means of a circuit completed from the line L1, thermostat 3%, right hand contact of the thermostat 34, conductor 37, electromagnet 31, conductor 38, to the other side of the line L2. This rotates the member 24 in a clockwise direction to increase the opening of the valves 19 and 18, thus increasing the size of the flame normally furnished when the thermostat 3-1 is in its neutral position.

If the thermostat 35 closes on the lower contact in response to heat requirements, this completes a circuit through the electromagnet 32 from the line L1, conductor e1, thermostat -35, lower contact of the thermostat 35, conductor 43, electromagnet 32, conductor 38, to the other side oi the line L2. This rotates the lever 2'? in a clockwise direction to further increase the opening oi. the valves 19 and it. The size of the flame is then at a maximum.

As the temperature within the room increases; the thermostat will respond to open the lower contact when the temperature reaches a prede termined value. The size of the flame will then be that called for by the outside thermostat 3d. 1f the temperature within the room should in= crease beyond that for which the upper contact is set, the thermostat will open to deenergize the relay 40, and thus deenergize the fuel supply mo tor 15 shutting down the burner until the room temperature again reaches that for which the thermostat is set to call for heat. v

If the temperature on the outside isabove that for which the thermostat 34 is set at its upper limit, the left hand contact will be closed to com= plete a circuit through the magnet 30 from the line L1, thermostat 34, left contact of the thermostat, conductor 36, electromagnet 3E9, conductor 38, to the other side of the line L2. This causes a rotation of the member 2% in a counter-clockwise direction to decrease the size of the valve openings and thus the size oi the flame. As

its

pointed out above, operation of the thermostat 35 to energize electromagnet 32 will affect the size of the flame to increase the same inany position in which the member 24 might be in response to the action of the thermostat 34.

Thus, it will be seen that in my control the oil burner is normally operated at a point such that the boiler operates normally between 25 and 50% full load which maintains the boiler operating at maximum efliciency. If the temperature on the outside increases or decreases the outside thermostat controls the system to vary the flame accordingly. The inside thermostat in response to inside temperatures, varies the flame in any of the positions at which the control is set by the outside thermostat, and in addition thereto deenergizes the burner when more-than suflicient heat is being furnished to the building being heated by the burner apparatus. This provides a very flexible system and one which operates the boiler and heating equipment at maximum efficiency.

While I have described my invention in concrete form and as operating in a specific manner in accordance with the provisions of the patent statutes, it should be understood that I did not limit my invention thereto since various modifications thereof will suggest themselves to those skilled in the art without departing from spirit of my invention and scope of which is set forth in the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States, is:

l. A house-heating system having a fuel-bdrm ing heater, a control for regulating the fuel supplied to said heater, an electro-responsive means for operating said control, switch means responsive to outside temperature for energizing said electrorresponsive means to vary the fuel supply inversely in accordance with predetermined variations of outside temperature, other electro-responsive means for operating said control, switch means responsive to inside temperature for energizing said other electro-responsive means to operate said control independently of said outside temperature-responsive means to vary the fuel supply inversely in accordance with predetermined variations of inside temperature, and means energized by said inside temperature-responsive switch means for controlling said fuelburning heater to start combustion and to stop combustion in response to predetermined inside temperatures.

2-. A heating system having a heat supply means, a control for said heat supply means biased to one position to cause said heat supply means to furnish heat at a given rate, a temperature responsive device responsive to outside tempera tures for causing movement of said control means in either direction to some other position from its biased position to vary the rate of heat supply, and means responsive to inside temperature for causing said control means to vary the rate of heat supply while said control means is in any of its positions called for by said outside temper= ature responsive device.

3. An oil burner heating system having means for delivering oil and air to the burner, a control means for said oil and air means, a member biased to a predetermined position for regulating said control means to furnish a predetermined supply of oil and air to said burner, temperature responsive means responsive to outside temperatures for moving said member in either direction from its biased position to another position to vary the oil and air supply, means carried by said member and operable independently thereof to move said control means to vary the air and oil supply with said member in any position called for by said outside temperature responsive means, and an inside temperature responsive device for controlling the means carried by said member.

4. A house heating burner control system having a fuel supply means, a control device for controlling the rate of fuel supplied by said means, means responsive to outside temperatures for operating said control device to predetermlne the rate of fuel supply inversely in accordance with variations of the outside temperature, an inside temperature responsive device for starting said fuel supply means to furnish fuel when the inside temperature decreases from a predetermined temperature and for stopping said fuel supply means when the inside temperature increases above said, predetermined temperature, and means controlled by said inside temperature responsive device for operating said control device to increase the rate of fuel supply determined by said outside temperature responsive device when the inside temperature decreases a predetermined amount from said predetermined temperature.

5. A house heating system having an electrically operated heat supply means; a control for said heat supply means, an electro-responsive means for operating said control, switch means for controlling energization of said electrically operated heat supply means to furnish heat when the inside temperature decreases from a predetermined temperature and to stop the sup" ply of heat when the inside temperature increases above said predetermined temperature, and a second switch means responsive to outside temperatures for energizing said electro-responsive means for varying the heat supply inversely in accordance with variations in the outside temperature.

6. A house heating system having a heat supply means, a control for said heat supply means including relatively movable members for operating said control, means responsive to outside temperatures for operating said movable mem= bers to vary the heat supply inversely with respect to varia'gions in outside temperature, and means responsive to inside temperatures for operating one of said relatively movable members for varying the heat supply inversely with respect to variations in the inside temperature and independently of said outside temperature responsive device.

A house heating system having a heat sup= ply means, means for controlling said heat supply means to furnish heat at a predetermined rate, a device responsive to outside temperatures for operating said control means to vary the rate of heat supplied inversely in accordance with variations of the outside temperature, and means responsive to inside temperature for start= ing and stopping said heat-supply means in accordance with predetermined variations of the inside temperature and for varying the rate of heat supplied from the rate initially determined by said outside temperature-responsive device and inversely in accordance with difierent variations of theinside temperature.

8. A burner control mechanism having a fuel supply means, valve mechanism for controlling the fuel supply, a control device therefor, electroresponsive means for operating said control device, a temperature responsive device responsive to outside temperatures for energizing said elec= tro-responsive means to-vary the fuel supply, other eleetro-responsive means for independently operating said control device and means respon sive to inside temperatures for energizing said other eiectro-responsive means to vary the rate of fuel supply to the burner and to control said ruel supply means to furnish fuel and to stop the. fuel supply.

9. A burner control mechanism having a fuel supply means, a control device therefor, a. valve mechanism for controlling the fuel supply includ ing a pair of relatively movable members con= nected to operate said valve mechanism, one of said members being carried by the other, a temperature responsive device responsive to inside temperatures for controlling said supply means to furnish fuel or to stop the fuel supply, and means responsive to outside temperatures for operating said members of said control device to vary the rate of fuel supply to the burner, said inside temperature responsive device operating one of said members of said control device to vary the fuel supply independently of said outside temperature responsive device.

10. A house heating system having a heat sup ply means, a control device for said heat supply means including a plurality of movable members, electro-responsive means for operating one of said members to vary the heating action of said heat supply means, a device responsive to outside temperatures for energizing said electroresponsive means for operating said member to supply heat inversely in accordance with out= side temperature, a second electro-responsive' means for independently operating another of the members of said control device to vary the heating action of said heat supply means be tween narrow limits to vary the heat supply inversely in accordance with inside temperatures, and an inside temperature responsive device for energizing said second electro-responsive means.

11. A control device for a burner house heat ing system having an electrical fuel supply motor, a valve mechanism for controlling the fuel sup" ply, a pair oi relatively movable members con-= nected with said valve mechanism to operate the same, electro-responsive means for moving said membersv to vary the fuel supply, switch means responsive to outside temperatures for energizing said electro-responsive means, a second electro-responsive means for independently cp= crating one of said relatively movable members to vary the fuel supply independently oi said first electr c-responsive means, and a switch means responsive to inside temperatm for energizing said second electro-responsive means, andconnections whereby said last switch means can energize and deenergize said electrical fuel supply motor to supply fuel and to stop the supply of fuel in response to predetermined inside temperatures.

outside temperature control means to vary the.

rate of iuel supply in accordance with inside temperature.

13. An oil burner heating system having a motor, means driven thereby for delivering oil and air to said burner, valves for regulating the supply of oil and air from the delivery means, a control device biased to open said valves to a predetermined position to furnish a predeter= mined supply of oil and air to said burner, an outside temperature responsive device for caus ing movement of said control device in either direction from biased position to vary the rate of oil and air supply in response to variations of outside temperatures and an inside temperature responsive device for independently varying said oil and air supply in response to inside temperatures.

it. An oil burner heating system having a motor, means driven thereby for delivering oil and air to said burner, valves for regulating the supply of oil and air from the delivery means, a control device biased "to open said valves to a predetermined position for furnishing a predetermined Supply of oil and air to said burner, an outside temperature responsive device for causing movement of said control device either way from biased position to vary the rate oi oil and air supply in response to variations of out side temperatures and an inside temperature responsive device for independently varying said oil and air supply in response to inside tempera= tures, said inside temperature responsive device controlling operation of said motor to stop the same when the inside temperature exceeds a pre determined value.

ELLIOT? ii). HARRENGTON.

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